1. Technical Field
The present invention relates to correction value setting methods, liquid ejecting apparatuses, printing systems and storage media having a program stored thereon.
2. Related Art
Liquid ejecting apparatuses such as inkjet printers have multiple nozzles for ejecting liquid and print a print image by ejecting liquid to a medium. The print image is formed by lining up a myriad of pieces of image that consist of dot rows.
By the way, it is difficult to manufacture the above multiple nozzles completely in the same way because of influence by variation in precision of manufacturing and the like, and the nozzles with various diameters may be manufactured for example. And in the case where the diameters of the nozzles vary, sizes of dots ejected from the nozzles and formed on the medium may vary. Because of the variation in dot sizes in this way, inconsistencies in density occur among pieces of image. As a result thereof, streaky density unevenness appears in the print image.
Therefore, technologies for suppressing such density unevenness and improving image quality of a print image are proposed (refer to JP-A-2005-205691). In a density unevenness correction method in JP-A-2005-205691, a pattern for detecting density unevenness is printed, and correction values are obtained based on density data of the printed pattern. Then, density correction is performed based on the obtained correction values.
By the way, some printers can print an image on various types of media. In the case where types of media vary, variations occur in degree of liquid absorption due to variations in surface treatment (such as coating) of the media and the like. As a result, density unevenness of a print image varies depending on the types of the media even if dots are formed by ejecting ink from the same nozzle.
Conventionally, the correction values were obtained by printing the pattern for detecting density unevenness on a particular type of medium (that is, a dedicated paper). On the other hand, no correction value was obtained for a medium of an unknown type other than the dedicated paper. Therefore, density unevenness of a print image printed on a medium other than the dedicated paper cannot be appropriately suppressed.